DNA purification is one of the most popular and significant procedures in molecular biology. The purification of DNA aims at separating the desired genetic material (chromosomal material) from other contaminants like proteins as well as RNA and cell membrane. This is an essential step in almost every molecular application and must be done correctly to get high-quality, usable DNA.
There are many different approaches for DNA purification. The selection of the method is contingent on a range of factors including the starting materials and downstream applications, costs and time limitations. The common plasmid and genomic purification protocols involve chemical treatment, enzymatic digestion or mechanical destruction of cells/tissues followed by salting out of the proteins and precipitating the DNA using alcohol.
Ethanol precipitation is an easy cheap and fast method of desalting and concentrated DNA. DNA molecules are aggregated in the presence of monovalent cations like sodium, and then they are removed from the solution using high concentrations ethanol. This method is used to remove salts, organic compounds, and other impurities. It is usually employed in conjunction with other purification methods.
Anion exchange chromatography is yet another popular method for DNA purification. DNA in a solution is bonded to positively charged resins due to the interaction between the negatively charged DNA phosphate backbone and the positively charged surface molecules of the resin. During the binding process removal of contaminants is accomplished making use of a strict washing process. The purified DNA then is eluted in low-salt conditions.